POLYPHASE CURRENTS.

37

revolution, two in each of its independent circuits; and the effectupon the motor is to shift the magnetic poles through three hun-dred and sixty degrees. It is obvious that if the four reversalsin the same order could be produced by each half-revolution ofthe generator the motor would make two revolutions to the gen-erator’s one. This would be readily accomplished by adding twointermediate poles to the generator or altering it in any of theother equivalent ways above indicated. The same rule appliesto generators and motors with multiple poles. For instance, if agenerator be constructed with two circuits, each of which pro-duces twelve reversals of current to a revolution, and these cur-rents be directed through the independent energizing-coils of amotor, the coils of which are so applied as to produce twelve

Fig. 29.

Fig. 28,

magnetic poles at all times, the rotation of the two will be syn-chronous ; but if the motor-coils produce but six poles, the movableelement will be rotated twice while the generator rotates once; orif the motor have four poles, its rotation will be three times asfast as that of the generator.

These features, so far as necessary to an understanding of theprinciple, are here illustrated. Fig. 28 is a diagrammatic illus-tration of a generator constructed in accordance with the inven-tion. Fig. 29 is a similar view of a correspondingly constructedmotor. Fig. 30 is a diagram of a generator of modified con-struction. Fig. 31 is a diagram of a motor of correspondingcharacter. Fig. 32 is a diagram of a system containing a gener-ator and several motors adapted to run at various speeds.